Such situation display systems are known in different versions. All of these systems or devices, however, are subject to substantial problems. For example, the high information density of a tactical map causes a display problem. As a result, conventional situation display systems have not been capable of providing a topographic map display with a high resolution of detail.
German Patent Publication No. (DE-OS) 3,426,505 discloses a sighting device or view finder mounted to a helmet relative to a given or fixed reference field or image. In this known device, the sighting symbol is produced on the screen of a helmet mounted cathode ray tube. A semi-permeable mirror focusses the sighting symbol into the eye with reference to the background. This reference system is gyro-stabilized and is located at the helmet. The system according to German Patent Publication No. (DE-OS) 3,426,505 is also subject to the limitation that the image detail or image area is too small, namely maximally only 40.times.40 cm, whereas an image detail or image area of at least 100.times.100 cm is required. Another disadvantage is the volume of the apparatus and its relatively substantial weight which makes it inconvenient as a helmet attachment.